1. Technical Field
This invention generally relates to dentistry. More particularly, the invention relates to dental implants. Specifically, the invention relates to an abutment clip that is detachably engageable over an abutment and includes at least one position indicator thereon that aids the dental surgeon in correctly orienting an abutment on an implant post.
2. Background Information
Over the last few decades dental technology has made great strides in providing improved ways to give people more natural-appearing and better secured artificial teeth or bridgework. (For the sake of clarity, both single artificial teeth and bridgework will be referred to hereinafter as “a prosthesis”). One of those improved technologies utilizes dental implants. A dental implant is a small titanium screw or bolt that is secured into the jaw bone to act as an anchor for a prosthesis. The implants are installed by drilling a small hole in the patient's jaw bone and then screwing an implant post into the bone surrounding the hole. The implant post is then covered with a flap of skin and the patient is sent away for a number of months to allow time for osseointegration to occur, i.e., for the living bone of the jaw to fuse to the implant post. The patient then returns to the dental surgeon who attaches an abutment to the implant post. The abutment is essentially a support that is secured to the implant post and extends upwardly and outwardly away from the jawbone. The prosthesis is then slipped over the abutment and is secured thereover by an adhesive cement.
A number of dental implant systems have been developed by different manufacturers, but most systems provide an implant post that has a specifically shaped post head and an internally threaded bore. The abutment is designed to interlock with the implant post and therefore includes a lower recess that receives the head of the implant post therein. A small screw is then inserted through the abutment and into the bore of the implant post. The screws used in these procedures are very small and are usually only about ¼ inch long. They are therefore extremely difficult to handle as the dental surgeon has to place the screw into a hole on the abutment and then hold both the screw and abutment on the implant post with one finger while trying to line up and begin to engage the threads on the screw with the other hand. Once the thread is started and there is no danger of dropping the screw and abutment, the dental surgeon will use a speed wrench to tighten the screw. When the abutment is secured in place, the prosthesis is attached to the abutment by way of an adhesive cement.
One of the key problems with the above procedure is the extremely limited access in various areas of the mouth, such as the region around the rear molars. The difficulty of this process is further compounded if the position for the implant is in the upper rear part of the mouth between two teeth. This position is more difficult because the dental surgeon faces the effects of gravity and, because the position of installation is toward the back of the mouth, there is the further complication of limited vision and access. If the prosthesis is to be installed between two teeth, the dental surgeon also only has access to the abutment from two sides because of the adjacent teeth. It is easier to position an implant to replace the rearmost molar in the mouth as this location permits the dental surgeon to have access to the abutment from three different sides. The dental surgeon is always concerned that the screw and abutment will fall out of the jawbone before the threads are engaged and that the patient might then accidentally swallow or inhale them. It is therefore commonplace for dental surgeons to position a cloth or other obstruction toward the back of the mouth to catch and retrieve any fallen components. It has been noted by the present inventors that a screw or other small component falls out during the initial thread capture as much as 20% of the time.
A second problem experienced by dental surgeons when doing this procedure is the problem of correctly orienting the abutment during installation so as to ensure that the prosthesis will end up in the correct orientation relative to the surrounding teeth. When either a single artificial tooth or bridgework is to be manufactured, an impression is made of the patient's jawbone after the implant posts have been installed. The impression is used to help the laboratory to produce a model. The model is used to produce a prosthesis that is correctly shaped, positioned and oriented relative to the teeth that are permanently seated in the jawbone. Dental implant systems are made so that the connection between the abutment and the implant post will reduce or prevent any rotation of the prosthesis in the mouth. In order to achieve this, some implant posts are manufactured with hexagonally shaped post heads, some have square post heads and others are triangular. However, this also means that the abutment can be engaged on the post head in more than one orientation. For example, if the abutment/implant connection is triangular in shape, then there are three possible orientations that the abutment may assume on the implant post. If the abutment/implant connection is square in shape, there are four possible positions that the abutment may assume on the implant post head. If the abutment/implant connection is hexagonal, then there are six possible orientations. What is subtle but very important to understand is that the abutment shape is rarely axially aligned with the implant post that is installed in the bone. This is because the implant post will be installed at whatever angle the surgeon feels is the best placement for that bolt in the jawbone. The dental lab must figure out the correct shape and angle that the abutment should be at so as to cause the prosthesis to be correctly aligned in the jawbone with any adjacent teeth. Furthermore, the angle of the abutment also needs to provide the dental surgeon with the necessary clearance to lower and glue the prosthesis into place, while still allowing for sufficient clearance from the adjacent teeth. So the abutment is custom made and carefully oriented on a plaster model.
Once the prosthesis is manufactured, it is returned to the dental surgeon attached to the actual plaster model that was made from the impression. The prosthesis is attached to the plaster model using the custom-made abutment. The dental surgeon has to remove the prosthesis, take special note the rotational position of the abutment on the model, detach the abutment from the model and then secure the abutment to the implant post in exactly the same rotational position in the patient's jaw. So, if the connection between the abutment and the implant post is a square connection, there will be four different possible positions for the abutment and the dental surgeon has to select the correct one of those four possible positions. This does not sound too difficult, but the abutment is so small and the shape and angle so subtle that it is difficult to get the abutment correctly oriented in the mouth. To make matters worse, the dental surgeon must also control and turn the tiny screw that it inserted through the abutment to set the abutment firmly on the implant post.
There is therefore a need in the art for an improved device for helping to correctly orient and install dental abutments on implant posts.